The present invention relates in general to medical equipment, and in particular to a new and useful monitoring device for for medical apparatus with pickups for at least one measured quantity and with means for signaling when given limit values are exceeded.
The health and life of patients may depend on the proper functioning of medical apparatus, as for instance respirators or anesthetizers. For this reason, monitoring devices are used for the most important functions thereof, which, when irregularities occur, give an optical or acoustic signal. The signal urges the personnel to initiate counter-measures.
A known monitoring device for respirators is equipped with a diaphragm cell connected to the gas transport lines of the respirator. A one-arm translatory lever senses the movements of the diaphragm and carries at its free end two contacts, each of which is opposite an adjustable contact screw. The contact screws are connected via lines to an alarm relay for each. During the operation of a respirator, the diaphragm cell is pressurized intermittently, so that the translatory lever executes an oscillating motion between the two contact screws. If the minimum pressure between the individual gas surges, decreases to a value below a limit value set by the contact screws, a contact is briefly closed which, via a delay unit, turns on one alarm relay after a certain number of closures of the contacts. On the other hand, if, when the maximum permissible gas pressure is exceeded, a contact between the translatory lever and the opposite contact screw is closed, the other alarm relay is turned on without delay. The two alarm relays actuate output means common to them, consisting of a buzzer and a warning light (See Swiss Pat. No. 461,711).
These output means do not address specifically the person monitoring the respirator but are perceived by all present in the vicinity. They may thus become a source of disturbance during delicate activities e.g. in the operating room. From the optical and acoustic alarm signal no clue can be derived as to which of the two limit values was exceeded, i.e. what kind of disorder is involved. Elimination of the reported disorder is thereby delayed.
In another known patient monitoring system for several persons, each of the persons to be monitored has his or her own individual monitoring unit assigned to him or her which is carried by the person, e.g. on the wrist. Several individual monitoring units cooperate with a central unit, remote-controlled by them, and having alarm signalling devices. The individual monitoring unit contains sensor means for monitoring a selected vital function, such as pulse, with production of the respective body state signal. To this end the individual monitoring unit contains signal processing means for signal processing, limit value determining means for generating an alarm signal when given limit values are exceeded, and transmitting means for relaying the alarm signal to the central unit. The relaying is done, e.g. by radio. The signal then consists of a code which indicates the emitting individual monitoring unit. The central unit contains signal receiving means, decoding means, and reporting means on which, in case of alarm, the emitting individual monitoring unit is indicated (displayed), optionally accompanied by a sound alarm (see W. German OS No. 25 35 858).
In this patient monitoring system, there is signaled to the monitoring person merely the occurrence of a limit value overstep at an identifiable monitoring point. The person is not, however, informed specifically or without disturbance to the environment. The monitoring person is tied to the location of the fixedly installed central unit and receives no specific information about the type and degree of the deviation. Also the information is limited to a single parameter.